The Chainlink


I am in favor of bicycles, bicycling and bicycle safety. I am opposed to bicyclists sustaining injuries and particularly head injuries that result in traumatic brain injury. More bicycles on streets and roadways make all bicyclists safer. Mandatory helmet
laws increase the rate of helmet use but decrease the number of bicyclists. The
health benefits of riding a bicycle far outweigh the risks of injury or death
(in “life years”). Bicycle helmets represent a design compromise that reduces
effectiveness in a crash in favor of lighter weight, comfort and ventilation.
If you are relying on a helmet to keep you safer while riding a bicycle, you
have skipped a number of important steps that can more effectively keep you “safer.”


I ordinarily keep my opinions about bicycle helmets to myself. I never tell anyone not to wear a helmet, though I sometimes wish the helmet people would reciprocate. The only reason I’m going “public” now is because the Active Transportation Alliance has
adopted a policy of making helmet use mandatory for its various fundraising
and/or sponsored events. The language currently being used is “I agree to wear a helmet suitable for cycling at all times during the bicycle tour. Those who refuse to
wear a helmet will not be permitted to ride and will not receive a
refund.”  The attorney side of me suspects this is an insurance underwriting requirement and the ATA needs to include this language to get a break on its liability premium (or possibly, a requirement to get any kind of coverage at all). And lest any of you think that the insurance underwriters are trying to make everyone safer, additional
requirements imposed on the policyholder are typically included in policies to
form a basis for excluding coverage.
The bicyclist side of me is disappointed that an organization which professes
to “advocate for transportation that encourages and promotes safety, physical activity,
health, recreation, social interaction, equity, environmental stewardship and
resource conservation,” has adopted a policy which runs contrary to that
mission statement. (I just became aware that “Bicycle Chicago Meet-up” and
Lee’s Big Shoulders Neighborhood Tours have the same requirement.)


I don’t want this post to be about me, but by way of background, my bicycling “experience” pre-dates the widespread use of helmets
(probably even the old “hairnets”). When I was a kid, you wore a helmet when you played football and when you batted in baseball, but that was pretty much it. In high school

and college, I competed in gymnastics (trampoline, no less), rugby and ski
racing - never wore a helmet, and neither did anyone else. My non-competitive
unhelmeted activities during this period of time included freestyle skiing with
lots of inverted aerials, and lots of vertical mogul runs. Bicycled some in
college, but never wore a helmet. Always wear a helmet snowmobiling, but
seriously, that’s a little like requiring people to wear a helmet when they go
skydiving. How did people survive such ultra-hazardous activities in the
pre-helmet dark ages? We took extra care not to hit our heads when we fell
down. Sometimes the old ways are the best ways.


This is not an academic paper for peer review, so I’m going to omit cites. If you’re really curious about one of them that you can’t find yourself or feel the need to rip on me in general, let me know and I’ll try to find it again. I know there are a lot of engineers and health care professionals on the chainlink, and I hope this post yields some constructive
criticism and feedback.


Bicycle helmets are mostly designed for slow, vertical falls. The testing methodology is to drop the weighted (11 lbs/5 kilos) helmet from a height of 1.2 meters onto a round anvil and/or a curb-shaped anvil and from a height of 2 meters onto a flat anvil. The headform measures the amount of impact attenuation when the helmet comes to rest, expressed in joules. A helmet which “passes the test” can permit a maximum of 98 joules at the headform. Failure threshold is 300 g, which happens to be the level at which you can expect to lose consciousness, and probably suffer some injury which hopefully will not be permanent.


Real world impacts are going to look a lot different from the testing methodology in that they are much more likely to include: multiple impacts, irregularly shaped “anvils,” and rotational forces (think crack the whip or water skiing outside of the wake when the boat turns). Real world impacts are also much more likely to occur with some significant horizontal speed (which has both advantages and disadvantages).


I bought my first helmet in about 1988. It was a thick styrofoam, poorly vented Specialized helmet which had a nylon fabric cover stretched over it and bore certification stickers to the 1984 Snell and ANSI standards. The unfinished styrofoam design was abandoned within five years for the hard shell finish due to the observation of increased neck and brain injury related to rotational forces exerted upon a helmet which was too “grippy” when it contacted pavement.


Bicycle helmet design must strike a balance between fashion and function. As the pressure has built for manufacturers to design “cooler” helmets (both from an aesthetic and ventilation standpoint), more and larger vents have been cut into the helmet surface. This has resulted in helmets which are indeed cooler and lighter, but which lack the structural integrity of my ugly old Specialized helmet. And penetration risk from rocks and tree branches when mountain biking?: Forget it; not even tested anymore; too many vents. Snell standards are gone, the certifying bodies in the U.S. are now CPSC and ASTM both of which require less energy attenuation than the Snell 95 standards
did. If you’re really serious about wearing a helmet to protect yourself from
traumatic brain injury, buy yourself a good, full-faced Arai, Bell or Shoei
motorcycle helmet-much better energy attenuation, and you also get the added
benefit of protection from facial injuries.


I wear a helmet approximately 25% of the time I ride a bike. My decision to wear a helmet is usually based on: a) likelihood of sustained speeds in excess of 18 mph; b) exceedingly long rides (>6 hours); and/or c) riding with a lot of strangers. I ALWAYS wear a helmet when I ride a mountain bike on trails. The only time I have ever hit my head when bicycling was when I was wearing a helmet. It’s not that I’m such a genius at predicting crashes, it’s simply because a helmet adds an additional 2-3 inches to the
radius of my head and that confuses my muscles and my sensory nervous system. I
have spent a lifetime “learning” where the perimeter of my head ends and I
can’t rewire my perceptual system to account for that extra 2-3 inches. I have
never been hit by a car, but I’m not counting being doored three times over the
years.


Fear is a very effective marketing tool. Whether you’re Rahm Emanuel not wanting to let a good crisis go to waste, or you’re the Bush administration trying to head off the impending invasion of the U.S. by Islamic extremists, a lot of things get “sold” in this country based on an inflated perception of danger. Bike accidents result in approximately 540,000 emergency room visits in the U.S. every year. Of those, 67,000 (12.4%) involve head injuries, and 8375 involve brain injuries [TBI] (1.5%). I can’t find the exact cite for this one folks, but it’s fairly representative of any given year in
the U.S. I’m going to make a pure guess that emergency room visits as an
accident index result in underreporting the total number of bicycle accidents
by a minimum of a factor of three; i.e. there are 3 times as many bicycle
accidents in the U.S. each year and that for every one that sends someone to
the emergency room, another two go unreported or at least don’t result in a
trip to the hospital. I’m also going to guess that an accident serious enough
to result in a TBI is unlikely to result in no hospital visit, so the 8375 TBI
number is probably pretty close to accurate. If this data and these guesses are
true, your risk of TBI is about 0.5% for any given accident, and probably even
lower than that.


Riding a bicycle can improve cardiovascular fitness and improve Body Mass Index, but it doesn’t change certain hard-wired physiological traits or cognitive functions that assist in making you a “safer” bicyclist. We all have differences in strength (including the composition of slow-twitch vs. fast-twitch muscles), balance, visual acuity, (including depth perception and ability to detect motion), hearing, proprioception, and judgment, to name just a few.  I have seen at least a half a dozen bicyclists in the past week, after dark, wearing a helmet, with no lights on the front or the back of their bicycle. I have told two of them they’re going to need a bigger helmet.


As stated, I am opposed to head injuries and particularly traumatic brain injuries. My brain has remained a solid second on my list of favorite organs since adolescence. If I’m ever in a bicycle accident with a car, I want to be dressed like the guy in “The Hurt Locker.” Most studies of the efficacy of bicycle helmets have found them to be effective at reducing the risk of head injury. In my estimation, that takes the risk down from remote to infinitesimal. 


Mandatory helmet laws increase the rate of helmet use, but reduce the number of cyclists on the road (Australia, New Zealand, Canada - British Columbia and Nova Scotia).


More cyclists on the road make all cyclists safer. In 1994, 796 bicyclists were killed in crashes with motor vehicles; in 2009, 630 bicyclists were killed in crashes with motor vehicles (-21%). Trips by bicycle have increased from 0.7% in 1990 to 1.0% in 2009 (+43%).


Portland reported this year that their rate of helmet wearing has increased to 80%, all through promotions and peer pressure. I have no problem with encouraging people
to wear helmets, strongly recommending that people wear helmets, but REQUIRING,
and EXCLUDING?  Can’t we all just get along?

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I fall into the camp of "one of those people" who credited a helmet with preventing a traumatic brain injury in this thread. I see your point to a degree, and would gladly concede that a better way to phrase the statement is to say a helmet "probably" helped prevent an even more serious traumatic brain injury.

Would it really have been a more serious TBI (rather than a minor/moderate concussion) without the helmet on, hard to say and even harder to prove. The ER doc certainly thought so, though. Kind of enough for me. In the end that experience of feeling like I may have escaped from something much much more serious by wearing one, mixed with the fact that they really aren't that uncomfortable IMHO, is enough to ensure I'll wear one for the rest of my life.




Dr. Doom said:
I wear magical hats and think others should, too, because why not. The most interesting thing to me, though, is always when you hear someone say, as someone here did, that while they got a concussion in a wreck, their helmet protected them from traumatic brain injury. A concussion is by definition a traumatic brain injury! If helmets were really effective people wouldn't get concussions while wearing them. Such is the power of faith in the magical hat, though, that even when they don't work they're credited for working.
I'm not advocating for mandatory helmet use, just to get that out of the way.

I'm curious, though, where the assumption comes from that by putting a helmet on, the average rider gets a "false sense of security or feeling of invincibility." I have just never known that be the case with any of the cyclists I know. In fact, it seems like the majority of people I see riding at night without lights, or pulling sketch maneuvers in traffic, are people riding without a helmet. While I have certainly also seen plenty of sketchy riders with helmets on, nothing has ever suggested to me that they are riding that way because they feel a helmet is some type of magical shield that will protect them against any injury. So my real question is, where does this idea come from that by asking someone to wear a helmet you are altering their behavior to be less risk-adverse while riding?


James Baum said:
Magic force-field.

Do I believe they do more good than harm? Probably -but only if they do not give the rider a false sense of security or feeling of invincibility. Helmets give such a minor increase in armor-protection to a limited area of the head in a very limited type of impact that ANY change in the behavior of the rider towards increased risk-taking will easily negate their fractional utility as a safety device and quickly become an albatross upon the rider's head instead of the magic talisman they believe it to be.

Someone just a few pages ago in this very thread stated that they forgot their helmet one time and they rode "very carefully" and were extremely paranoid enough to change their behavior and routes when they were riding without their magic hat.

IMHO, they'd be much better off "forgetting" their force field at home more often and just continuing riding "very carefully" like they didn't have their helmet on all the time. They'd be safer riding all the time like any crash is going to cause serious harm to them because helmet or not getting hit by a car is going to HURT A LOT and most probably do them harm.

I've seen this almost exact same statement in other forums and heard it from people I've talked to.

People feel more safe with their helmet and take more risks with it on than when they don't have it -the fact that they ride more carefully when they don't have a magic hat on only proves that point to me.

It's only human nature. The same has happened with cars. As tire technology has improved, ABS and traction control come online, and a host of other safety features drivers have just moved the bar up and driven faster and harder while using up any safety advantage the new technology has given them.

I've been driving since the late 70's and I've seen this phenomenon for myself.

Riders feel they are safer with that helmet on and make decisions to take more risks in other places due to the sense of security the helmet gives them.



ad said:
I'm not advocating for mandatory helmet use, just to get that out of the way.

I'm curious, though, where the assumption comes from that by putting a helmet on, the average rider gets a "false sense of security or feeling of invincibility." I have just never known that be the case with any of the cyclists I know. In fact, it seems like the majority of people I see riding at night without lights, or pulling sketch maneuvers in traffic, are people riding without a helmet. While I have certainly also seen plenty of sketchy riders with helmets on, nothing has ever suggested to me that they are riding that way because they feel a helmet is some type of magical shield that will protect them against any injury. So my real question is, where does this idea come from that by asking someone to wear a helmet you are altering their behavior to be less risk-adverse while riding?



I think your creating a little bit of a false dichotomy here. Your argument assumes the person in question that was extra cautious while riding without a helmet was doing something risky or ill-advised while riding with a helmet, which I don't think is necessarily true. When someone says they rode "very carefully" or cautiously when they forgot their helmet, my first thought would be that the person probably rode slower and took a path home that had less traffic. That doesn't mean the normal speed they ride and the normal path they take when wearing a helmet is actually more dangerous or any less safe in reality. In other words, just because someone says they were extra cautious when they forgot their helmet on a ride doesn't mean they aren't cautious when they remember to bring it.


James Baum said:
Someone just a few pages ago in this very thread stated that they forgot their helmet one time and they rode "very carefully" and were extremely paranoid enough to change their behavior and routes when they were riding without their magic hat.

IMHO, they'd be much better off "forgetting" their force field at home more often and just continuing riding "very carefully" like they didn't have their helmet on all the time. They'd be safer riding all the time like any crash is going to cause serious harm to them because helmet or not getting hit by a car is going to HURT A LOT and most probably do them harm.

I've seen this almost exact same statement in other forums and heard it from people I've talked to.

People feel more safe with their helmet and take more risks with it on than when they don't have it -the fact that they ride more carefully when they don't have a magic hat on only proves that point to me.

It's only human nature. The same has happened with cars. As tire technology has improved, ABS and traction control come online, and a host of other safety features drivers have just moved the bar up and driven faster and harder while using up any safety advantage the new technology has given them.

I've been driving since the late 70's and I've seen this phenomenon for myself.

Riders feel they are safer with that helmet on and make decisions to take more risks in other places due to the sense of security the helmet gives them.



ad said:
I'm not advocating for mandatory helmet use, just to get that out of the way.

I'm curious, though, where the assumption comes from that by putting a helmet on, the average rider gets a "false sense of security or feeling of invincibility." I have just never known that be the case with any of the cyclists I know. In fact, it seems like the majority of people I see riding at night without lights, or pulling sketch maneuvers in traffic, are people riding without a helmet. While I have certainly also seen plenty of sketchy riders with helmets on, nothing has ever suggested to me that they are riding that way because they feel a helmet is some type of magical shield that will protect them against any injury. So my real question is, where does this idea come from that by asking someone to wear a helmet you are altering their behavior to be less risk-adverse while riding?



Not all serious accidents are caused by other road users and helmets reduce more than just a small amount of force.

My dad was commuting in NYC and one of those traffic counting tubes was not properly secured and managed to catch his wheel as he went over it. He flew over his handlebars, collapsed a lung on impact, and had a bunch of road rash down his side. The back of his helmet was cracked where he hit it.

Obviously, a helmet is not a magic force field that saved him from all injuries, but he was at least able to get up on his own and take himself to the hospital. If he hit hard enough to collapse a lung, I'm confident that his helmet is the only thing that saved him from having a bunch of graymatter splattered on the pavement.

It's absurd to say that helmets are marginally effective or to make the comparison that we should just wear them all the time. It's simply not possible to go 15-20mph on foot and the speed of travel will increase the impact when you hit the ground. That seems to make biking inherently a little more dangerous than walking. Personally, I'll trade that risk for the ability to get around faster and put on my helmet to partially mitigate it. Even if you educate other road users and are very alert, stuff happens and vigilance can't protect against everything. Don't wear a helmet if you don't want to, but don't be surprised if you get your own Darwin award for it.


I'm not advocating for mandatory helmet laws for adults, but I have a somewhat twisted argument on why they might be useful: because you'll cause less disruption to traffic if you can walk away from an accident on your own than if you have to be carted off in an ambulance.


Jamais716 said:
Not all serious accidents are caused by other road users and helmets reduce more than just a small amount of force.

My dad was commuting in NYC and one of those traffic counting tubes was not properly secured and managed to catch his wheel as he went over it. He flew over his handlebars, collapsed a lung on impact, and had a bunch of road rash down his side. The back of his helmet was cracked where he hit it.

Obviously, a helmet is not a magic force field that saved him from all injuries, but he was at least able to get up on his own and take himself to the hospital. If he hit hard enough to collapse a lung, I'm confident that his helmet is the only thing that saved him from having a bunch of graymatter splattered on the pavement.

It's absurd to say that helmets are marginally effective or to make the comparison that we should just wear them all the time. It's simply not possible to go 15-20mph on foot and the speed of travel will increase the impact when you hit the ground. That seems to make biking inherently a little more dangerous than walking. Personally, I'll trade that risk for the ability to get around faster and put on my helmet to partially mitigate it. Even if you educate other road users and are very alert, stuff happens and vigilance can't protect against everything. Don't wear a helmet if you don't want to, but don't be surprised if you get your own Darwin award for it.


I'm not advocating for mandatory helmet laws for adults, but I have a somewhat twisted argument on why they might be useful: because you'll cause less disruption to traffic if you can walk away from an accident on your own than if you have to be carted off in an ambulance.

Good post. As someone who's specialized in brain injury rehabilitation, I tend to mention diapers before disruption to traffic.
Speaking of diapers, hitting one's head hard enough to break/crack a helmet could very easily also cause serious spinal injury. Such an accident can cause paralasis and other issues where a diaper might become de rigor for the rest of a person's stay on planet earth.

Back and neck braces are seen more often in the motorized 2-wheel safety community and are commonly used in racing today. I wonder why they are not yet pushed by the bicycle safety community or is Big Neckbrace not as heavily into donating large sacks of money to "Bicycle Safety" as Big Helmet is?





H3N3 said:
Good post. As someone who's specialized in brain injury rehabilitation, I tend to mention diapers before disruption to traffic.
Since this discussion has grown to encompass cycling habits and not just the efficacy of helmets, it's probably worth mentioning this again. One of the best things you can do to ensure your own safety while riding is to frequently change your routes to common destinations. Print that sentence and tape it to the inside of your helmet.
Please expand on this thought.

Michael Perz said:
Since this discussion has grown to encompass cycling habits and not just the efficacy of helmets, it's probably worth mentioning this again. One of the best things you can do to ensure your own safety while riding is to frequently change your routes to common destinations. Print that sentence and tape it to the inside of your helmet.
Complacency...

Familiarity breed contempt.

Most people tend to go into autopilot and aren't paying attention. They'd do themselves much more good by becoming more mindful about their surroundings and what is going on around them than relying on a security-blanket of limited utility like a flimsy bike helmet to get them through the inevitable crash as long as they have their helmeted-head in a the clouds believing they are safely ensconced in their magic force-field.

Always be hyper-vigilant when out on the mean streets. Helmet or not they are extremely dangerous to everyone -even the pedestrians. Once one unplugs themselves from being aware it is only a matter of time before reality plugs you back into its cold embrace violently.



Michael Perz said:
Since this discussion has grown to encompass cycling habits and not just the efficacy of helmets, it's probably worth mentioning this again. One of the best things you can do to ensure your own safety while riding is to frequently change your routes to common destinations. Print that sentence and tape it to the inside of your helmet.
James, please lay off whatever is causing you to be delusional about helmeted riders being delusional.

Thanks.

James Baum said:
Complacency...

Most people tend to go into autopilot and aren't paying attention. They'd do themselves much more good by becoming more mindful about their surroundings and what is going on around them than relying on a security-blanket of limited utility like a flimsy bike helmet to get them through the inevitable crash as long as they have their helmeted-head in a the clouds believing they are safely ensconced in their magic force-field.

Michael Perz said:
Since this discussion has grown to encompass cycling habits and not just the efficacy of helmets, it's probably worth mentioning this again. One of the best things you can do to ensure your own safety while riding is to frequently change your routes to common destinations. Print that sentence and tape it to the inside of your helmet.
I'm not sure I can agree with this. I realize that there could be some truth to the notion that we go on "autopilot" when we take the same route over and over, however, taking the same route seems good for me. My commute has a lot of stops (I'm a dog walker) and I'm on a somewhat tight schedule. No one wants me to get to their house after 4 pm, so being on the same route allows me avoid anything unexpected--crossing a main arterial street, riding on a road that's full of potholes, dealing with riding through a school zone at 2:30--just for a few examples.

I've found that after years of riding the same roads every day of the week, I am more likely to *know* the road. I know where the potholes are, where the sight lines might be tricky, when there's a difficult intersection, when I have to encounter lots of kids after school, etc. It's sometimes a surprise when a road I usually take is being repaved but other than that, I can't say that there are many times when I'm zoned out on my bike. At least not while I'm actually moving.

Complacency seems a lot more likely when I'm in the car. I have had cancellations on my dog walking route and I'll still drive as if I'm going to the client who canceled. For some reason, when I'm on my bike, this never happens. I always know where I'm going and I like knowing the route's going to basically stay the same. I've been tweaking it for years (because clients come and go) and when I do that it gets better all the time, too.

James Baum said:
Complacency...

Familiarity breed contempt.

Most people tend to go into autopilot and aren't paying attention. They'd do themselves much more good by becoming more mindful about their surroundings and what is going on around them than relying on a security-blanket of limited utility like a flimsy bike helmet to get them through the inevitable crash as long as they have their helmeted-head in a the clouds believing they are safely ensconced in their magic force-field.

Always be hyper-vigilant when out on the mean streets. Helmet or not they are extremely dangerous to everyone -even the pedestrians. Once one unplugs themselves from being aware it is only a matter of time before reality plugs you back into its cold embrace violently.



Michael Perz said:
Since this discussion has grown to encompass cycling habits and not just the efficacy of helmets, it's probably worth mentioning this again. One of the best things you can do to ensure your own safety while riding is to frequently change your routes to common destinations. Print that sentence and tape it to the inside of your helmet.

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